A couple of years ago, I had toe nail fungus. Medical doctor prescribed pills.  I took every day, for maybe 3 months?  I don't recall the name. However, I do recall having to get blood tests to check my liver.  So, I presume this is the same medication that your doctor is referring to.  It cleared up the toenail fungus, and I didn't have any issues with my liver. None that I am aware of.

Toenail fungus developed again this winter. I just had a doctor appointment about 10 days ago.  I mentioned it to my current doctor. He prescribed ciclopirex, also known as PenLac.  This is a topical medication, not a pill.  I don't need blood tests to check my liver with this medication. I haven't started it yet, so I don't know if it works. I do believe he said I need to use it for 3 months. 

You may want to ask your medical doctor about Penlac.  See if might be something that could work for you.